Apparatus for use in the production of spiral-welded tubes or pipes

ABSTRACT

An apparatus for use in the production of spiral-welded tubes or pipes, which comprises a triple roller bending system of a forming body including an outer guide roller device and an inner guide roller device. A first row of rollers is at least individually supported on a beam hydraulically adjustable in a substantially vertical direction on hydraulic cylinders. The adjustment of the displacement stroke of each of the cylinders is effected in such manner that a triple roller bending system is set in accordance with a previously determined relationship between oil pressure and displacement stroke.

United States Patent 1 Claussen [4 1 Sept. 16, 1975 .4] APPARATUS FORUSE IN THE PRODUCTION OF SPIRAL-WELDED TUBES OR PIPES [75] Inventor:

[73] Assignee: Berliner Maschinenbau-AG vormals L. Schwartzkopff,Berlin, Germany Mar. 9, 1973 Lorenz Claussen, Berlin, Germany [22]Filed:

21 Appl. No.1 339,868

[30] Foreign Application Priority Data Mar. 13, 1972 Germany "2212744[52] US. Cl. 228/17; 228/5; 228/9; 219/62; 72/170 [51 Int. Cl... B23k37/04; B2lC 37/06; 1321c 37/08 [58] Field of Search....; 228/5, 15, 1 7,8, 9; 29/4773; 2l9/62; 72/l70 [56] References Cited UNITED STATESPATENTS 1,659,754 2/1928 Thorsky 219/62X 3,093,103 6/1963 Berkeley.228/17 X 3,146,331 8/1964 Schubert..... 228/17 X 3,208,138 9/1965Eckhardt 29/4773 Primary ExaminerFrancis S. Husar Assistant Examiner-GusT. Hampilos Attorney, Agent, or Firm-Ernest G. Montague; Karl F. Ross;Herbert Dubno [5 7 ABSTRACT An apparatus for use in the production ofspiralwelded tubes or pipes, which comprises a triple roller bendingsystem of a forming body including an outer guide roller device and aninner guide roller device. A first row of rollers is at leastindividually supported on a beam hydraulically adjustable in asubstantially vertical direction on hydraulic cylinders. The adjustmentof the displacement stroke of each of the cylinders is efiected in suchmanner that a triple roller bending system is set in accordance with apreviously determined relationship between oil pressure and displacementstroke.

1 Claim, 2 Drawing Figures APPARATUS FOR USE IN THE PRODUCTION OFSPIRAL-WELDED TUBES OR PIPES.

The present invention concerns apparatus for use in the production ofhelically welded tubes in which the displacement or stroke of thebending tool can be manually or automatically adjusted in operation sothat even with very different properties of material, various.

tubes (pipes) can be produced without strain or tension or with adesired amount of tension. I

Forming tools for the production ofspiral-welded tubes having an outerand ,inner guide are already known and comprise a triple roller bendingsystem and guide rollers which are arranged either in the form of anouter cage or inner star. Forming bodiesare already known in which thetriple roller bending system is adjusted in dependence upon the contactpressure, measured by means of pressure boxes between shaped (deformed)sheet metal and guide rollers behind the triple roller bending system sothat the said contact pressure and, consequently, the amount ofspringing up of the pipes is as low as possible. The disadvantage ofthis arrangement is that thepressure measurementas a value indicator ofthe displacement of the triple roller bending system is too inaccurateand, in addition, depending on the position of the pressure. measuringboxes, forrex ample on the welding gap control of the machine, can beinfluenced so that t he measuredpressureis nota measure of the contactratios of the deformed sheetmetal to the guide rollers. Correspondingadjustment .of the triple roller bending system would lead to incorrectresults. i

The present invention however, relatesto a forming body, the tripleroller bending system of which is constroke control are effected in thetriple roller bending,

system itself.

The essential difference between conventional arrangements and that ofthe present application is there-v fore that in the first case of thecontact pressure sul: jected to many secondary influences is usedbehindthe triple pressurebend ing system, and in the second casev according tothe present invention, a-theoretically and- /or experimentallypredeterminedstroke is.used in the triple rollerbending systemasastandard value forthe correct positioning of the bending system,

The arrangement of the present invention comprises a triple rollerbending system, thefront andmiddle.

bending beam' of which comprising roller supports which are preferablyhydraulically adjusted, either over is adjusted, dependantly on theproperty of the material, corresponding to a stroke dependance readilyand correctly ascertainable experimentally for each type of steel, forproducing tubes without tension. If, for example, the strength of thematerial rises, then the bending moment rises and therewith the actionof force from the band on the hydraulic pressure cylinder of thearrangement of the present invention. At the same time the pressure inthe closed stroke-connolled system also ing amount.

rises without anyinitially change in the-positioning of the stroke;

The adjustment of the triple roller bending system is not effected inthe conventional manner, i.e., purely pressure-dependantly, since themaintenance of a certain pressure on the bending roller and,consequently, also a certain bending moment, still fail to guarantee auniform springing up amount e.g. almost zero, or makes possible themaintenance of anydesired spring- Aswell known, the band material forshaping the tube is plastically bent-over and when the strain or flowlimit of the material is reached during the plastic bending-over, thenecessary bending moment no longer rises or-only rises so slightlythatthis change in the bending moment can no longer be measured.reliably in a pipeforming machine. Y

The amount of springing-up (or in) of a pipe is determined, exactly asin the bending over of the band material so that the bending overdiameter necessary for the springing up measurement zero or for anyother desired springing up measurement is maintained. The latter bendingover-diameter depends, however, on the fluctuations of theithickness ofthe material, which are relatively slight, and on the fluctuations inthe strength of jointly or each roller separately in a vertical orinclined direction. This adjustment is effected preferably withstroke-contrblled hydraulic cylinders. .The stroke of the hydraulicpistons is not controlledrin the already known manner 'so that contactpressure indicator used as a value indicator, is reduced as much aspossible behind the triple roller 'bending'system, butin accordance withthe present invention, in such manner that the bending the material,which are relatively large and which is measured by theforce on therollers of the bending system just as the fluctuations in the thicknessof the mate rial are measured. With variations. in this force, thebending system musttherefore be adjusted and it must be again pointedout that. the force does not change with such an adjustment.

In accordance with the present invention, the-triple roller bendingsystem is therefore positioned either by vertical or slightly inclinedadjustment 0f the front bending beam alone or with an oppositelydirected movement of the middle bending beam together so that a' changeof stroke eorresponds to the rise in pressure in the closedstrokecontrolled system with the increase in the strength of thematerial, said change of stroke being obtained experimentally and/ortheoretically for each material quality so that pipes without tensionare produced or pipes with a desired amount of springing up or tensionare produced. Accordingly, the same applies to positioning in areduction of the material strength. The preferred hydraulic adjustmentof the bending beam or beams of the individual roller cylinder orcylinders can be effected manually or automatically by correspondingpositions of the control valves. For example, a'stroke scale found foreach quality of steel can be arranged around the pressure gauge saidscale associating the correct position with each change of pressure.

The invention will be described further, by way of example, withreference to the accompanying drawing in whichi. v

FIG. 1 is a schematic cross-section through a forming arrangemermandFIG. 2 is aperspectiveview of a particular embodivThe present inventionutilizes a three roller bending system'which is generallyformed of aseries of rollers, namely: a first row, a-second upper row and a thirdrow which are arranged to form desired bending of a band of pipematerial.

t A guide cage is formed by rows of rollers 4 which rows are adjustedinitially for a desired diameter of finished pipe and preferably remainunchanged in operation.

Similarly, a row of rollers 3 associated with the triple roller bendingsystem is adjusted for the desired finished pipe diameter and preferablyremain unchanged in operation. 1

In contrast to this, row of rollers 2 is adjustable in operation so thatthey bend incoming band 5 to a diameter which is less than the desiredfinished diameter. In the embodiment shown, the adjustment of the roller1 is effected by a hydraulic cylinder 7 which is secured to the machineframe 6 and has a piston rod 8 which carries the roller 1. Each of therollers is therefore guided and positioned by a cylinder. However, in analternative arrangement (not shown), all the rollers of the first rowmay be carried by a common beam and this beam. can be hydraulically ormechanically adjusted. I

In the embodiment shown, the adjustment indication for the position ofthe row 1 is effected by a bar 9 which actuates the feeler 10 of ahydraulic copy feeler ll (e.g.- a valve of a serv'omechanismsee page 407of Servomechanism Practice, McGraw-Hill, 1960). The copy feeler 11 ismechanically connected to the piston rod 8 by a rod. If, for example,the bar 9 is raised, the feeler 10 is pressed in and permits the flow ofoil to raise thepiston and, consequently the roller 1. Since the entirecopy feeler also rises with the roller 1, the raising of the roller 1 isconcluded when the feeler l0 resumes the previous position relative tothe bar 9, that is, when the roller 1 has directly copied the adjustmentof the bar'9.-

It must beemphasised that an electro-hydraulic or electro-mechanical orother adjustment may also be provided, instead of the described directhydraulic copying.

The fluctuation in the strength of the material and/or the fluctuationsin the thickness of the incoming band 5 determine the forces on therollers 1,2 and 3. This force is read from the pressure gauge 13 andcorresponding pressure gauges may be also provided for the row 2.

For a specific pipe and quality of material reference to the pressuregauge 13 gives an indication of the strength of the material. Thecorrect bending-over diameter associated with the material or thepositioning of the rows of rollers 2 and/or 1 is obtained experimentallyand/or theoretically and can be given manually or by an automaticindication, for example, by a cam disc acting on the bar 9 or acorresponding member for row 2, which in turn adjusts the rollers 2and/or 1 accordingly.

After leaving the triple roller bending system that is upon leaving therow of the rollers 3, the tube expands to the (greater)finished diameteror until it comes into contact with the rollers 4. It is always possibleto obtain and indicate the bending-over diameter so that the expandeddiameter (in which therefore no uncompensated inner strains remain inthe pipe wall) is equal to the desired finished-pipe diameter. In thiscase, the springing-up measurement is zero. In practice it may bepreferable to leave a small amount of pressure ori the rollers 4 toguide the pipe and in order to maintain the finished pipe diameter moresimply and accurately. This pressure on the rollers 4 is not directlymeasured, however, but maintained by a correspondingly correctedpositioning of rows 1 and 2.

According to FIG. 1, the triple roller bending system is arranged sothat the incoming band runs horizontally or substantially horizontallywhich results in a simpler machine construction and the bent-over on theroller 3 merges tangentially into the finished diameter. Since it isonly here that the incoming band runs parallel to the already finishedpipe with which it is to be welded, the welding point is just ahead oron the other side of the roller 3. This position of the welding point inthe rising band is simultaneously the preferred position for protectivegas tack or finished welding. The arrangement shown is thereforepreferably provided for socalled tack-welding machines.

However, it' must be emphasised that the forming systern of the presentinvention is also suitable for sub merged arc welding. Since in suchwelding the welding point must lie inor near the lowest point, thetriple roller bending system is turned further forwardly towards theband inlet). In this case the band must enter at an incline from aboveor first outwardly over the first roller that is, must be bentoppositely since in each case the sheet metal must be bent over withinthe triple roller bending-system to a diameter which is less than thefinished diameter. I i

FIG. 2 is a part perspective view of an embodiment of the presentinvention and shows in detail a preferred supporting arrangement of asingle roller 1 (or for a roller 2) by respective hydraulic cylinders.The same references are used in FIG. 2 as in FIG. 1 when referring toidentical parts.

Furthermore the embodiment of FIG. 2 is supplemented relative to FIG. Iby footplate 21 by which the unit is connected to the machine frame.Also, a track rod 22 is provided for adjusting all the rollers 1parallel to the band inlet angle by way of the bolt 23 and the rod 8.

An important feature of FIG. 2 is that the bar 24 (which indicates ordictates the position) is not supported on the machine frame, but hasasupport (not shown)--separate from the frame supporting the tripleroller bending system. The advantage of this arrangement is that theelastic deformation of the machine frame originating from the very greatbending forces, no longer influences the rated value indication.

Further advantages of the individual supporting arrangement of theroller include that defects in a supporting arrangement no longer haveany adverse influence on the machine; and that the roller either pressescontinuously fully against the 'band, but is unable to bend it reliablyalone or it moves into the other position whilst its load is received bythe other rollers. A repair is preferably effected by exchanging acomplete unit and for this purpose the band need not be removed from themachine.

Finally it is possible to operate the cylinders and preferably the uppercylinders, hydraulically 'so that they can deflect pressures toward thehydraulic system upon the exceeding of a certain pressure. In thismanner the (raised) cross welding seam can pass without raising morethan one roller and without overloading this or its supporting system orthemachine frame.

Another embodiment of the present invention resides in that the band isarranged to run into the bending system horizontally or substantiallyhorizontally and is bent over here to a diameter which is less than thefinished diameter so that the entering band is higher than the lowerpoint of the finished pipe.

I claim:

1. In an apparatus for the production of helicalwelded pipe having guidemeans defining a circular path for a metal band and welding means forwelding each turn as formed to previous turns of the band to form ahelical seam pipe, the improvement which comprises: a

bending means forimparting a bend to a oncoming band, said bending meanscomprising a first roller initially encountering said band, a secondroller downstream of said first roller and subsequently encounteringsaid band and a third roller downstream of said second roller andencountering said band thereafter, said first and third rollers engagingan external surface of the band to be bent and said second rollerengaging an internal surface thereof, said rollers defining a circulararc having a radius of curvature less than the radius of said pipe;pressurizable means for displacing one of said first and second rollersto adjust the curvature of the bend formed in said band, said guidemeans and the others of said rollers having a common frame;

a support independent of said frame for carrying said one of saidrollers;

a device responsive to the position of said one of said rollers forcontrolling said pressurizable means; and

adjusting means including-a bar mounted on said support and between saidsupport and said device for setting the position of said one of saidrollers in accordance with characteristics of the band, said devicedetecting the spacing of said one of said rollers from said bar tocontrol said pressurizable means.

=I l I

1. In an apparatus for the production of helical-welded pipe havingguide means defining a circular path for a metal band and welding meansfor welding each turn as formed to previous turns of the band to form ahelical seam pipe, the improvement which comprises: bending means forimparting a bend to a oncoming band, said bending means comprising afirst roller initially encountering said band, a second rollerdownstream of said first roller and subsequently encountering said bandand a third roller downstream of said second roller and encounteringsaid band thereafter, said first and third rollers engaging an externalsurface of the band to be bent and said second roller engaging aninternal surface thereof, said rollers defining a circular arc having aradius of curvature less than the radius of said pipe; pressurizablemeans for displacing one of said first and second rollers to adjust thecurvature of the bend formed in said band, said guide means and theothers of said rollers having a common frame; a support independent ofsaid frame for carrying said one of said rollers; a device responsive tothe position of said one of said rollers for controlling saidpressurizable means; and adjusting means including a bar mounted on saidsupport and between said support and said device for setting theposition of said one of said rollers in accordance with characteristicsof the band, said device detecting the spacing of said one of saidrollers from said bar to control said pressurizable means.